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Update binary_search_edge.py

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code for 10.3.2-2.
This commit is contained in:
Lihuahangvampire 2024-07-08 16:34:34 +08:00
parent f4a6d2127c
commit 1349fc28c2
1 changed files with 16 additions and 1 deletions
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17
codes/python/chapter_searching/binary_search_edge.py
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@ -33,7 +33,18 @@ def binary_search_right_edge(nums: list[int], target: int) -> int:
return -1 return -1
# 找到 target ，返回索引 j # 找到 target ，返回索引 j
return j return j
def binary_search_edge(nums: list[int], target: int) -> int:
"""二分查找target左右边界"""
# 当数组中不包含target时,索引i,j最终分别指向首个大于,小于target的元素
# 左侧边界查找 = 查找target-0.5 ;返回索引i
# 右侧边界查找 = 查找target+0.5 ;返回索引j
i = binary_search_insertion(nums, target - 0.5)
j = binary_search_insertion(nums, target + 0.5) - 1
# 当数组中存在元素target时,左侧边界<=右侧边界
if i > j:
return -1, -1
else:
return i, j
"""Driver Code""" """Driver Code"""
if __name__ == "__main__": if __name__ == "__main__":
@ -47,3 +58,7 @@ if __name__ == "__main__":
print(f"最左一个元素 {target} 的索引为 {index}") print(f"最左一个元素 {target} 的索引为 {index}")
index = binary_search_right_edge(nums, target) index = binary_search_right_edge(nums, target)
print(f"最右一个元素 {target} 的索引为 {index}") print(f"最右一个元素 {target} 的索引为 {index}")
# 二分查找左右边界
for target1 in [6,8,10]:
left_index,right_index = binary_search_edge(nums, target1)
print(f"元素 {target1} 的左右边界索引分别为 {left_index}, {right_index}")